Photographic supersensitized silver halide emulsions

ABSTRACT

LIGHT-SENSITIVE PHOTOGRAPHIC SILVER HALIDE EMULSIONS ARE SPECTRALLY SENSITIZED WITH A TRICARBOCYANINE DE IN WHICH THE MESO CARBON ATOM OF THE METHINE LINKAGE OF THE DYE IS ATTACHED TO THE NITROGEN ATOM OF AN AMINO GROUP WHICH FORMS AN ENAMINE WITH THE METHINE LINAGE OF THE DYE; SAID EMULSION CONTAINING, SUPERSENSITIZER, A SULFONATED POLYNUCLEAR AROMATIC ORGANIC COMPOUND, A SILVER HALIDE REDUCING AGENT, AN AZAINDENE OR A COMBINATION OF SUCH SUPERSENSITIZERS.

United States Patent Oflice 3,695,888 Patented Oct. 3, 1972 3,695,888 PHOTOGRAPHIC SUPERSENSITIZED SILVER HALIDE EMULSIONS Gary L. Hiller, Hilton, Cynthia G. Ulbing, Fairport, and John E. Starr, Webster, N.Y., assignors to Eastman Kodak Company, Rochester, NY.

No Drawing. Continuation-impart of application Ser. No. 860,394, Sept. 23, 1969. This application May 28, 1970,

Ser. No. 41,569

Int. Cl. G03c N US. Cl. 96-123 10 Claims ABSTRACT OF THE DISCLOSURE This application is a continuation-in-part of our copending US. patent application Ser. No. 860,394 filed Sept. 23, 1969, now abandoned.

This invention relates to novel photographic emulsions, and more particularly to spectrally sensitized photographic silver halide emulsions.

It is well known that photographic emulsions can be spectrally sensitized to infrared radiation. See Mees and James, The Theory of the Photographic Process, 3rd Edition, The MacMillan Company, 1966, pages 198 and 199. It is highly desirable that such emulsions exhibit good sensitivity to longer wavelength infrared radiation, and have high sensitivity throughout the infrared region. In addition, such emulsions should retain high sensitivity to infrared radiation on storage. The emulsions should also have high sensitivity to blue radiation. Heretofore, emulsions sensitized to infrared radiation have been deficient in one or more of the foregoing respects. Accordingly, it would be highly desirable to provide improved infrared sensitized photographic silver halide emulsions.

One object of this invention is to provide infrared sensitive photographic silver halide emulsions.

Another object of this invention is to provide photographic silver halide emulsions which are stable on storage.

Still another object of this invention is to provide photographic silver halide emulsions which have high sensitivity to long wavelength infrared radiation.

Still another object of this invention is to provide supersensitized photographic silver halide emulsions.

Another object of this invention is to provide photographic silver halide emulsions which retain high sensitivity to infrared radiation on storage.

A further object of this invention is to provide supersensitized photographic silver halide emulsions which have low fog levels.

Another object of this invention is to provide supersensitized emulsions which have high sensitivity to blue radiation.

Other objects of this invention will be apparent from the disclosure herein and the appended claims.

.In one embodiment of this invention, a photographic silver halide emulsion is sensitized with a supersensitizing combination comprising: at least one tricarbocyanine dye in which the meso carbon atom of the methine linkage of the dye is attached to the nitrogen atom of an amino group which forms an enamine with the methine linkage of the tricarbocyanine dye; and at least one supersensitizer selected from the group consisting of a sulfonated polynuclear aromatic organic supersensitizer; an azaindene; and, a silver halide reducing agent. Photographic emulsions supersensitized in accordance with this invention exhibit excellent speed in the infrared region of the spectrum; have high speed in the blue region of inherent emulsion sensitivity; and, retain excellent sensitivity to blue and infrared radiation on storage.

Tricarbocyanine is used herein as a word of art and includes dyes having the amidinium-ion chromophoric system (see Mees and James, The Theory of the Photographic Process, Third Edition, 1966, page 201). Typically, such dyes have two nitrogen containing heterocyclic nuclei which are joined by a straight chain methine linkage having seven methine groups. The carbon atom of the central methine group of the methine linkage is referred to herein as the meso carbon atom of the methine linkage.

The word enamine is used herein to refer to the group See Advances in Organic Chemistry, Methods and Results, vol. 4, Raphael, Taylor and Wynberg, 1963, Interscience, page 3, and Fieser and Fieser, Advanced Organic Chemistry, Reinhold Publishing Corp., 1961, pages 494- 499.

Any tricarbocyanine dye in which the meso carbon atom of the methine linkage is attached to the nitrogen atom of an amino group which forms an enamine with the methine linkage can be used in the practice of this invention. The preferred tricarbocyanine dyes used herein have the following formula:

1 Q, Xe

wherein n and m each represents an integer of from 1 to 2; R and R are selected from the group consisting of an alkyl group, including substituted alkyl, (preferably a lower alkyl containing from 1 to 4 carbon atoms), e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, decyl, dodecyl, etc., and substituted alkyl groups (preferably a substituted lower alkyl containing from 1 to 4 carbon atoms), such as a hydroxyalkyl group, e.g., fl-hydroxyethyl, w-hydroxybutyl, etc., an alkoxyalkyl group, e.g., p-methoxyethyl, w-butoxybutyl, etc., a carboxyalkyl group, e.g., p-carboxyethyLw-carboxybutyl, etc.; a sulfoalkyl group, e.g., fl-sulfoethyl, w-sulfobutyl, etc., a sulfatoalkyl group, e.g., B-sulfatoethyl, w-sulfatobutyl, etc., an acyloxyalkyl group, e.g., fl-acetoxyethyl, 'y-acetoxypropyl, w-butyryloxybutyl, etc., an alkoxycarbonylalkyl group, e.g., B-methoxycarbonylethyl, w-ethoxycarbonylbutyl, etc., or an aralkyl group, e.g., benzyl, phenethyl, etc., or, any aryl group, e.g., phenyl, tolyl, naphthyl, methoxyphenyl, chlorophenyl, etc.; X represents an acid anion, e.g., chloride, bromide, iodide, thiocyanate, sulfamate, perchlorate,

p-toluenesulfonate, methylsulfate, etc., and can be included in R or R for example, when R or R represents a sulfoalkyl or carboxyalkyl group; Z and Z each represents the non-metallic atoms necessary to complete the same or diiferent 5- to G-membered heterocyclic nucleus such as used in cyanine dyes, which nuclei can contain a second hetero atom such as oxygen, sulfur, selenium or nitrogen, such as the following nuclei: a thiazole nucleus, e.g., thiazole, 4-methylthiazole, 4-phenylthiazole, S-methylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4-(2thienyl)thiazole, benzothiazole, 4-chlorobenzothiazole, S-chlorobenzothiazole, 6-chlorobenzothiazole, 7-chlorobenzothiazole, 4-methylbenzothiazole, S-methylbenzothiazole, G-methylbenzothiazole, S-bromobenzothiazole, 6-bromobenzothiazole, 5- phenylbenzothiazole, 6-phenylbenzothiazole, 4-rnethoxybenzothiazole, S-methoxybenzothiazole, 6-methoxybenzothiazole, 5 -iodobenzothiazo1e, 6 iodobenzothi'azole, 4- ethoxybenzothiazole, S-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6- dimethoxybenzothiazole, 5,6-dioxymethylenebenzothiazole, S-hydroxybenzothiazole, 6-hydroxybenzothiazole, naphthol[2,1 d]thiazo1e, naphtho- [1,2 d] thiazole, 5 methoxynaphtho[2,3 d]thiazole, 5 ethoxynaphtho[2,3 d]thiazole, 8 methoxynaphtho- [2,3-d]thiazole, 7-methoxy-naphtho[2,3-d1thiazole, 4- methoxythianaphtheno 7',6' 4,5 thiazole, etc.; on oxazole nucleus, e.g., 4-methyloxazole, S-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole, benzoxazole, 5-chlorobenzoxazole, S-methyl'benzoxazole, 5-phcnylbenzoxazole, G-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5 methoxybenzox azole, S-ethoxybenzoxazole, 5-chlorobenzoxazole, 6-methoxybenzoxazole, S-hydroxybenzoxazole, -6-hydroxybenzoxazole, naphtho[2,1-d]xazole, naphtho[1,2-d]oxazole, etc.; a selenazole nucleus, e.g., 4-methylselenazole, 4-phenylselenazole, benzoselenazole', -chlorobenzoselenazole, S-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetnahydrobenzoselenazole, naphtho[2,1-d]selenazole, naphtho [1,2-d]selenazole, etc.; a thiazoline nucleus, e.g., thiazoline, 4-methylthiazoline, etc.; a pyridine nucleus, e.g., 2-pyridine, S-methyl-Z-pyridine, 4-pyridine, 3-methyl-4- pyridine, etc.; a quinoline nucleus, e.g., 2'quinoline, 3- methyl-Z-quinoline, S-e'thyl-Z-quinoline, -6-chloro-2-quinoline, 8-chloro-2-quinoline, 6-rnethoxy-2-quinoline, S-et'hoxy-Z-quinoline, 8-hydroxy-2-quinoline, 4-quinoline, 6- methoxy-4-quino1ine, 7-methyl-4-quinoline, 8-ch-loro-4- quinoline, l-isoquinoline, 3,4-di'hydro-l-isoquinoline, 3- isoquinoline, etc.; a 3,3-dialkylindolenine nucleus, e.g., 3,3 dimethylindolenine, 3,3,5 trimethylindolenine, etc.; and an imidazole nucleus, e.g., .irnidazole, l-alkylimidazole, 1 alkyl 4 phenylimidazole, 1 alkyl 4,5 dimethylimidazole, benzimidazole, l-alkylbenzimidazole, 1-ary1-5,6-dichlorobenzimidazole, 1-alkyl-1H-naphth[1,2- d]imidazole, 1-aryl-3H-naphth[l,2-d]imidazole, l-alkyl-S- methoxy-lH-naphth[1,2-d1imidazole, etc.; Q represents a divalent linkage, such as ethylene, trimethylene, orthophenylene, which linkage can be substituted, for example, with halogen, an elkyl or an alkoxy group of one to four carbon atoms; and, R and R taken separately each represents a member selected from the group consisting of alkyl and aryl, and, taken together R and R represent the non-metallic atoms required to complete a heterocyclic ring containing from 5 to 6 atoms, e.g., a morpholino group, a thiomorpholino group, a piperindino group, a piperazinyl group, (preferably a 4-alkyl-1-piperazinyl group such as methyl, ethyl, ethoxycarbonyl, propyl or butyl groups, or an 4-aryl-1-piperazinyl group such as a 4-phenyl-1-piperazinyl group) a pyrrolidinyl group, an indolinyl group, a tetrahydroquinoyl group and a decahydroquinoyl group. Especially good results are obtained when Z and Z each represent a benzoxazole, a naphthothiazole nucleus, or a benzothiazole nucleus; Q represents an ethylene linkage; and, R and R are taken 4 together and represent a piperazinyl group, a 4-ethoxycarbonyl-l-piperazinyl being preferred.

Typical specific tricarbocyanine dyes useful in the' practice of this invention are set out in Table A below:

TABLE A 11-(i-ethoxycarbonyl-l-piperazinyl)-3,3'-diethyl-10,12-

ethyleneoxatricarbocyanlne perchlorate.

II 3,3'-diethyl-10,12'ethylene-ll-(4-methyl-i-piperazinyl) oxatrlcarbocyanine perchlorate.

III 3,3'-diethyl-10,12-ethylene-1l-(4-methy1-1-piperazinyl)- thiatricatbocyanine perchlorate.

IV 11-(i-ethoxycarbonyl-l-piperezinyl)3,3'-diethyl-l0,l2-

ethylene-5,5'-diphenyl0xatricarbocyanine erchlorate.

V Anhydro-ll-(4-ethoxycarbonyl-l-piperazinyl -10,12-ethylene-3,3-di(3-suliopropyl)thlatricarbocyanine hydroxide.

VI Anhydro-10,12-ethylene-11-(i methyl-l-piperaziuyl)3,3-

di(3-suliopropyl)oxatriearbocyanine hydroxide.

VIL. Anhydro-10,12-ethylone-l1-(4-methyl-1-piperazinyl)-3,3-

di(3-suliopropyl)thlatriearbocyanine hydroxide.

VIII 11-(A-ethoxyearbonyl-l-piperazinyl)-3,3-diethyl-10,1%

ethylenethiatrlcnrbocyanlne perchlorate.

IX 11-(4-phenyl-1-piperazinyl)-3,3-diethy1-10,12-0rthophenylenethiatrlearbocyenine p-toluene sulionate.

X Anhydro-11-dlbutylamino-10,i2-ethy1eue-3,3-di(3-suliopropyl)thiatricarbocyanine hydroxide, sodium salt.

XI 3,3-diethyl-10,12-ethylene-11-(1-pyrrolidinyl)thietricarbocyanine iodide.

... l0,12-ethylene-1,1,3,3,3,3-hexamethyl-ll-(l-pyrrolidinyl)- indotrlcarbocyenlne iodide.

XIII 3,Z;l-gliethyl-10,l2-ethylene-1I-piperidinothiatricarbocyanino XIV 3,3'-diethyl-10,12ethylene-11-morphollnothiatrlcarbocyanine iodide.

XV 3,3-dlethyl-l1-piperidino-10,1Z-trlmethylenethiatrlcarbocyanineiodl e.

XVI 3,3-diethyl-l0,12-ethylene-11-(l-indolinyl)oxatrlcarbocyanine perchlorate.

XVII 3,3-diethyl-l0,12-ethylene-11-[1-(1,2,3,4-tetrahydroquinolylloxatrlcarbocyanine perchlorate.

XVIII I1-diethylamino-3,3-diethyl-10,12-ethylenethiatriearbocyanine perchlorate.

XIX 1I-diethylemlno-IO,12-ethylene-l,11 ,3,3 ,3 ,3 -hexamethyliudotricarboeyanine perchlorate.

XX 3,3-diethyl-l0,l2-ethylene-11-[1-(1,2,3,4-tetrahydroquinolyl)]4,5,4, 5-dibenzothiatricarbocyanine perchlorate.

XXI ll-diphenylamino-3,3-diethyl-lO,12-ethyleneoxatricarbocyanine perchlorate.

XXII 1l-dimethylamino-3,3-diethyl-10,1Hthylenethiatriearbocyanine perchlorate. XXIIL- 3,3-diethyl-10,12trimethylene-1l-thiomorpholinooxathiatrlcarbocyanine perchlorate.

XXIV 3,3'-diethyl-lO,12ethylene-11-(l-decahydroquinolyl)4,4-

tricarbocyanlne perchlorate.

XXV Anhydro-ll-(4otherycarbonylpiperezin-l-yl)-10,12-ethyleue-3,3-bis (3-suliopropyl)-5,6,5,6-dibenzothiatrlcarbocyanine hydroxide, triethylamlne salt.

with one mol. of an enamine salt of Formula III below:

III. R

to obtain a compound having Formula IV below:

IV. a

One mol. of the compound of Formula IV can then be reacted with one mol. of a compound having Formula V below:

ll CHI-O x9 I VI to obtain a compound having Formula I above. In the above formulas, X, n, m, Z Z Q, R R R and R have the meanings given above. The reactions are advantageously conducted in a suitable solvent, such as acetone or acetic anhydride, and preferably in the presence of a basic condensing agent, such as triethylamine, and at elevated temperatures, such as the refluxing temperature of the reaction mixtures. Further details on the preparation of dyes employed in this invention appear in Jeffreys US. patent application Ser. No. 314,864 filed Oct. 10, 1963 now U.S. Pat. 3,483,195 issued Dec. 9, 1969 and corresponding to French Pat. 1,410,864; Jeffreys U.S. patent application Ser. No. 518,010 filed Jan. 3, 1966 now U.S. Pat. 3,506,655 issued Apr. 14, 1970, and corresponding Belgian Pat. 674,800; Fumia et al. US. patent application Ser. No. 574,947 filed Aug. 25, 1966 now US. Pat. 3,482,978 issued Dec. 9, 1969 and corresponding Belgian Patent 702,840; and, Fumia et al. US. patent application Ser. No. 860,395, filed Sept. 23, 1969 now abandoned, and entitled sensitizing Dyes and Photographic Emulsions and Elements Containing Said Dyes, and continuation-in-part application thereof Ser. No. 22,708, filed Mar. 25, 1970 now US. Pat. 3,623,881 issued Nov. 13, 1971.

One class of supersensitizers useful in practicing this invention are the polynuclear aromatic compounds containing at least one sulfo group. The term polynuclear aromatic as used herein is intended to mean 2 or more benzene rings fused together (for example, as in naphthalene, pyrene, etc.) or at least 2 benzene rings or aromatic rings directly joined together (for example, as in diphenyl, terphenyl, quaterphenyl, etc.) or through an ali phatic linkage. Such sulfonated derivatives can conveniently be represented by the following general formula:

wherein D represents a polynuclear aromatic group as defined above and M represents a hydrogen atom or a watersoluble cation salt group (e.g., sodium, potassium, ammonium, triethylammonium, triethanolammonium, pyridinium, etc.). Among the most useful of the sulfonated derivatives embraced by Formula IVa above are the compounds represented by the following general formula:

N N lit-W W-NH NH-f TR" 1 01M SO;M y

wherein M has the values given above and R R R R each represents a hydrogen atom or a substituent group, such as hydroxyl, aryloxyl (e.g., phenoxyl, o-toloxyl, p-sulfophenoxyl, etc.), alkoxyl (e.g., methoxyl, ethoxyl, etc.), a halogen atom (e.g., chlorine, bromine, etc.), a heterocyclic radical (e.g.,. morpholinyl, piperidyl, etc.), an alkylthio group (e.g., methylthio, ethylthio, etc.), an arylthio group (e.g., phenylthio, tolylthio, etc.), a heterocyclylthio group (e.g., benzothiazylthio, etc.) an amino group, an alkylamino group (e.g., methylamino, ethylamino, propylamino, dimethylamino, diethylamino, dodecylamino, cyclohexylamino, fi-hydroxyethylamino, di-fl-hydroxyethylamino, B-sulfoethylamino, etc.), an arylamino group (e.g., anilino, o-, m and p-anisylamino, o-, mand p-chloroanilino, o-, mand p-toludino, o-, m-, and p-carboxyanilino, hydroxyanilino, sulfonaphthylamino, 0-, mand p-aminoanilino, p-acetamidoanilino, etc.), etc.

Compounds of Formula Vb wherein R11, R R and/ or R each represents a heterocyclylamino group (e.g., 2-benzothiazoleamino, 2-pyridylamino, etc.) can also be used in practicing my invention.

Another group of sulfonated derivatives which are useful in practicing my invention are those represented by the following general formula:

VIa. 0

wherein R is an acylamido group (e.g., acetamido, sulfobenzamido, 4-meth0xy-3-sulfobenzarnido, 2-ethoxybenzamido, 2,4-diethoxy, benzamido, p-tolylamido, 4-methyl- Z-methoxybenzamido, l-naphthoylamino, 2 naphthoylamino, 2,4-dimethoxybenzarnido, 2-phenylbenzamido, 2- thienylbenzamido) or a sulfo group, R represents an acylamido group (e.g., as defined by R above), or a sulfoaryl group (e.g., sulfophenyl, p'-sulfodiphenyl, etc.) and R represents a hydrogen atom or a sulfo group, said compound containing at least one sulfo group.

Compounds of Formula Vb which can advantageously be employed in practicing my invention have been described in one or more of the following representative patents.

U.S.: 2,171,427, Aug. 29, 1939; 2,473,475, June 14, 1949; 2,595,030, Apr. 29, 1952; 2,660,578, Nov. 24, 1953; 2,945,762, July 19, 1960. British: 595,065; Nov. 26, 1947; 623,849, May 24, 1949; 624,051, May 26, 1949; 624,052, May 26, 1949; 678,291, Sept. 3, 1952; 681,642, Oct. 29, 1952; 705,406, Mar. 10, 1954.

The products of Formula Vb have been previously employed in the textile field, and are sold under such trade names as Leucophor B, Calcofiuor White, MR, Tinopal (SP, WR, BV277, 2B, GS, NG), Blancofor SC, Hiltamine (BSP, N, 801., 6T6), and the like.

The dibenzothiaphenedioxide compounds of Formula VIa have, in general, been previously described in the prior art. See, for example, US. Pats. 2,573,652; 2,580, 234; and 2,563,493. Further examples of the preparation of such compounds are given in I. E. Jones, J. Spence, and J. A. Van Allan, US. Pat. 2,937,089, issued May 17, 1960. Other examples of sulfonated derivatives embraced by Formula IVa above which can advantageously be used in my invention can be prepared according to the methods described in appliction Ser. No. 575,160. Still other examples of compounds represented by Formula IVa above which can be used in my invention have been previously described in B. H. Carroll, J. E. Jones, and J. Spence, US. Pat. 2,950,196, issued Aug. 23, 1960. (See, in particular, the compounds of Formulas II, III and IV of that patent.)

Compounds selected from those of Formula Va above wherein B represents a 2-benzotriazoly1 group can be prepared according to methods previously described in the prior art. See, for example, U.S. patent to Zweidler et a1. 2,713,057, dated July 12, 1955; Keller et al., U.S. Patent 2,684,966, dated July 27, 1954; Zweidler et al., U.S. Patent 2,784,197, dated Mar. 5, 1957; and Keller et al., U.S. Patent 2,784,183, dated Mar. 5, 1957. A somewhat related group of compounds containing a 2-benzotriazolyl group which can be used in my invention have been previously described in U.S. Patent 2,733,165. Such compounds are embraced by Formula IVa above.

Typical sulfonated derivatives embraced by Formulas IVa, Va, and VIa above are (chemical formulas are given for various types to aid in identification):

(1) a sulfonated triazolestilbene, e.g., of the type shown in U.S. Patent 2,713,057.

Co a HOaS 3,7-bis(2-phenylbenzamido)-2,8-disulfodibenzoyl)-benzidine-2,2'-disulfonic acid thiophene-5,5-dioxide (13) 3,7-bis(2-thienylamido)-2,8-disulfodibenzothiophene dioxide sodium salt (l4) 3- [4- (4-methoxy-3-sulfobenzamido) phenyl] -7- 4- methoxy-3-sulfobenzamido) dibenzothiophene dioxide sodium salt (15 chrysene-6-sulfonic acid sodium salt (16) pyrene-3-sulfonic acid sodium salt (17) Phenanthrene-3-sulfonic acid sodium salt (18) 2,3-dimethylnaphthalene-l-sulfonic acid sodium salt 19) 4- [4-phenoxy-6- (B-hydroxyethylamino -s-triazin-2- ylamino]-4'-[4chloro-6-di(B-hydroxyethyl)amino-striazin-Z-ylamino]stilbene-2,2'-disulfonic acid (20) 2,8-bis [4- 4-sulfoanilino -6-hydroxy-s-triazin-2- ylamino] carbazole (21) 4,4'-bis (4,6-di (B-hydroxyethylamino) -s-triazin-2- benzidine-2,2-disulfonic acid (22) 2-laurylamino-4,6-di(4-sulfoanilino)-s-triazine 23) 4,4-bis{4- [4'- (N',4"-sulfobenzyl-N'-ethyl) aminoanilino] 6-hydroxy-s-triazin-2-ylamino}- stilbene-2,2'-disulfonic acid (24) 5-acetarnido-2-(4-styryl-3-sulfo)phenyl-1,2,3-

benzotriazole sodium salt (25) 2,7-diacetamido-3,6-disulfodibenzothiophene-5,5-

dioxide sodium salt (26) 4-sulfo-o-terphenyl sodium salt (Lour. Organ. Chem.,

vol. 14 (1949), p. 163) (27 pyrene-3-(4-methoxy-3-sulfostyryl)ketone sodium salt ('28) 3,7-bis(4-methyl-2-methoxybenzamido)-2,8-

disulfodibenzothiophene-5,5-dioxide sodium salt As can be seen above, many of the sulfonated derivatives are employed in the form of their water-soluble salts, such as alkali metal (e.g., sodium, potassium, etc.) salts, or ammonium or amine (e.g., triethylamine, triethanolamine, pyridine, aniline, etc.) salts. By thus using these derivatives, they can be added to the emulsions in substantially neutral aqueous solutions without disturbing the pH of the emulsions.

In accordance with the practice of this invention, any reducing agent (Le, a material capable of reducing silver halide) can be employed which supersensitizes photographic silver halide emulsions containing tricarbocyanine dyes of the type employed herein. Particularly good results are obtained with dihydroxy substituted reducing agents. Typical dihydroxy compounds which can be employed in the practice of this invention are selected from the group consisting of the benzenes, gamma-lactones, pyronimides, tetronimidcs, furans and pyrroles, which contain at least two hydroxyl groups.

Typical useful dihydroxy substituted compounds which can be utilized include hydroquinone, resorcinol, pyrocatechol, S-methylpyrocatechol, toluhydroquinone, naphthalenediols, etc.; 'y-lactones such as ascorbic acid, isoascorbic acid, etc.; 3-hydroxy tetronimides; 3,4,5-trihydroxy-5,6-dihydro-pyronimides; and amino hexose reductones wherein the moiety comprising the subject reductones can be represented wherein: R and R can be an alkyl radical, preferably having 1 to 8 carbon atoms or together the necessary atoms to make a heterocyclic radical with the nitrogen atom, preferably having a 5 to 6 atom nucleus and including a second nitrogen atom or an oxygen atom such as morpholino, piperazino, pyrrolino, pyridino, pyrimidino, piperidino and the like.

Typical suitable tetronimidcs, pyronimides and amino hexose reductones are set out in Table B:

TABLE B 5-Phenyl-3-hydroxy tetronimide 5- (4-carboxyphenyl)-3-hydroxy tetronimide, 5-(3,4-dimethoxyphenyl)-3-hydroxy tetronimide,

-(n-buty1)-3-hydroxy tetronimide 5-(2-furyl)-3-hydroxy tetronimide (S-a-furyl-3,4-dihydroxy-2-imino-2,5-dihydrofuran),

and the like; 5,6-di-n-butyl-3,4,5-trihydroxy-5,6-dihydro-pyronimide,

5,6-di-n-butyl-3,4,5-trihydroxy-5,6-diyhdro-pyronimide,

5 ,6-di-morpholino-3,4,5-trihydroxy-5,6-dihydro pyronimide,

5,6-(2-sulfopheny1)-3,4,5-trihydroXy-5,6-dihydropyronimide, and the like;

Dimethylamino hexose reductone Di-n-butylamino hexose reductone Di-n-hexylamino hexose reductone Morpholino hexose reductone Piperazino hexose reductone Pyrrolino hexose reductone Piperidino hexose reductone and the like.

The tetronimides and pyronimides such as mentioned above may be prepared by the methods described in British Patent No. 782,304, Swiss Patent No. 322,985, and in Helv. Chim. Acta, 39, 1780 (1956). The above, and still other B-hydroxy tetronimides and 3,4,5-trihydroxy- 5,6-dihydro-pyronimides that are suitable, are disclosed in Salminen, U.S. Patent No. 3,330,655, issued July 11, 1967.

The amino hexose reductones of the invention are derived from sugars, especially D-glucose, although other six carbon or hexose reducing sugars such as D-galactose, D-mannose, D-fructose, L-sorbose or the like can be used. A typical method for preparing the subject reductones comprises heating in a reaction medium substantially free of water a hexose reducing sugar and an aliphatic or cyclic secondary amine in the presence of an acidic reductone-forming catalytic agent such as phosphoric acid, boric acid, acetic acid, succinic acid or the like. The removal of three molecules of water results during the formation of the subject amino hexose reductones. The mentioned reductones and other related suitable reductones and methods for preparing such are described in Hodges, U.S. Patent No. 2,936,308.

Emulsions containing an enamine tricarbocyanine dye of the type described above can be supersensitized with an azaindene, such as a triazaindene, a tetraazaindene or a pentaazaindene. Hydroxy and amino substituted azaindenes are especially useful. Representative useful azaindenes include those described in the following references:

Allen et al. U.S. Patent 2,735,769, Feb. 21, 1956 Allen et al. U.S. Patent 2,743,181, Apr. 24, 1956- Tinker et al. U.S. Patent 2,835,581, May 20, 1958 Reynolds U.S. Patent 2,756,147, July 24, 1956 Carroll et al. U.S. Patent 2,743,180, Apr. 24, 1956 Zeitschrift fur Wiss. Phot. 47, 2-28 (1952) Carroll et al. U.S. Patent 2,716,062, Aug. 23, 1955 Allen et al. U.S. Patent 2,772,164, Nov. 27, 1956 Allen et al. U.S. Patent 2,713,541, July 16, 1955 Tinker et al. U.S. Patent 2,835,581, May 20, 1958 Carroll U.S. Patent 2,743,180, Apr. 24, 1956 Fry U.S. Patent 2,566,658-9, Sept. 4, 1951 Heimbach et al. U.S. Patent 2,444,605-7, July 6, 1948 Especially useful tetrazaindenes include those having the following formula:

6 2CH 5 3a 8888/ in which R is an alkyl group, e.g., methyl, ethyl, propyl, butyl, etc. Some particularly useful azaindenes are listed below:

4-hydroXy-2(4-pyridyl)-6-methyl-l,3,3a,7-tetrazaindene Heimbach et al. U.S. Patent 2,449,225-6, Sept. 14, 1948 4-hydroxy-6-methyl-1,2,3,3a,7-pentazaindene 5-amino-2- (p-carboxyphenyl)-7-hydroxy- 1,3,4,6-pentazaindene 2,4-dihydroxy-6-methyl-1,3a,7-triazaindene 2,5 -dimethyl-7-hydr0xy-1,4,7a-triazaindene 5-amino-7-hydroxy-2-methyl-1,4,7a-triazaindene 5-carboxy-4-hydroxy-1,3,3a,7-tetrazaindene 1,2-bis(4-hydroxy-6-rnethyl-1,3,3a,7-tetrazaindene S-yl ethane 1,2,3,4-tetrakis(4-hydroxy-6-methyl-1,3,3a,7-

tetrazaindene-2-yl)butane 2-amino-5-carboxy-4-hydroxy1,3,3a,7-tetrazaindene 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene As noted above, azaindenes function as supersensitizer in emulsions containing enamine tricarbocyanine dye. In some emulsions, the azaindene is advantageously used in combination with reducing agent, or preferably sulfonated organic compound supersensitizer, to produce emulsions having the best overall characteristics in terms of inherent emulsion speed, infrared speed, low fog and storage stability. 8

According to the invention, one or more of the sulfonated organic compounds or one or more of the azaindenes or one or more of the reducing agents, and one or more of the enamine tricarbocyanine dyes of the invention, are added separately or together to light-sensitive photographic silver halide emulsions to supersensitize the emulsions.

Particularly good results are frequently obtained when both sulfonated organic compound and reducing agent are employed. In some emulsions, excellent results are obtained with the combination of an azaindene with a sulfonated organic compound supersensitizer. In other instances, it is desirable to supersensitize emulsions with tricarbocyanine dye and sulfonated organic compound, reducing agent and azaindene.

The optimum concentration of enamine tricarbocyanine dye and supersensitizer or combination of supersensitizers can be determined in a manner well known to those skilled in the art by measuring the sensitivity of test portions of the same emulsion, each portion containing a different concentration of dye and supersensitizer or mixture of supersensitizers. As a general guideline, good results are obtained with about .01 to 1 gram dye per mole of silver and about 25 to 2000 mg. and preferably 50 to 1000 mg. per mole of silver of the sulfonated organic supersensitizer or reducing agent, and, from 1 to 8 grams, and preferably from 2 to 4 grams, per mole of silver, of azaindene.

Silver halide emulsions supersensitized in accordance with this invention can comprise silver chloride, silver bromide, silver bromoiodide, silver chlorob-romoiodid'e or mixtures thereof. Such emulsions can be coarse, medium or fine grain (or mixtures thereof) and can be prepared by any of the well-known procedures, e.g., single jet emulsions or double jet emulsions. Useful emulsions include Lippmann emulsions, ammoniacal emulsions, thiocyanate or thioether ripened emulsions such as those described in Nietz et al. U.S. Patent 2,222,264, Illingsworth U.S. Patent 3,320,069, and McBride U.S. Patent 3,271,157; or, cubic grain emulsions, such as those described by Kline and Moisar, Journal of Photographic Science, volume 12, page 242 et seq. or Markocki, The Spectral Sensitization of Silver Bromide Emulsions on Diiferent Crystallographic Faces, Journal of Photographic Science, volume 13, 1965; or, Illingsworth British Patent 1,156,193 published June 25, 1969.

The silver halide emulsions supersensitized with the dyes of this invention can be unwashed or washed to remove soluble salts. In the latter case the soluble salts can be removed by chill-setting and leaching or the emulsion can be coagulation washed, e.g., by the procedures described in Hewitson et al. U.S. Patent 2,618,556; Yutzy et al. U.S. Patent 2,614,928; Yachel U.S. Patent 2,565,418; Hart et al. U.S. Patent 3,241,969; and Waller et al. U.S. Patent 2,489,341.

Photographihc emulsions containing supersensitizing combinations in accordance with this invention can be sensitized with chemical sensitizers, such as with reducing agents; sulfur, selenium or tellurium compounds; gold, platinum or palladium compounds; or combinations of these. Suitable chemical sensitization procedures are described in Shepard U.S. Pat. 1,623,499; Waller U.S. Pat. 2,399,083; McVeigh U.S. Pat. 3,297,447; and Dunn U.S. Pat. 3,297,446.

The supersensitized silver halide emulsions of this invention can contain speed increasing compounds such as polyalkylene glycols, cationic surface active agents and thioethers or combinations of these as described in Piper U.S. Pat. 2,886,437; Chechak U.S. Pat. 3,046,134; Carroll et al. U.S. Pat. 2,944,900; and Gotfe U.S. Pat. 3,294,540.

Silver halide emulsions containing the supersensitizing combinations of this invention can be protected against the production of fog and can be stabilized against loss of sensitivity during keeping. Suitable antifoggants and stabilizers, which can be used alone or in combination. include the thiazolium salts described in Staud U.S. Pat. 2,131,038 and Allen U.S. Pat. 2,694,716; the azaindenes described in Piper U.S. Pat. 2,886,437 and Heimbach U.S. Pat. 2,444,605; the Mercury salts described in Allen U.S. Pat. 2,728,663; the urazoles described in Anderson U.S. Pat. 3,287,135; the sul-focatechols described in Kennard U.S. Pat. 3,236,652; the oximes described in Carroll et al. British Pat. 623,448; nitron; nitroindazoles; the mercaptotetrazoles described in Kendall et al. U.S. Pat. 2,403,927, Kennard et al. U.S. Pat. 3,266,897 and Luckey et al. U.S. Pat. 3,397,987; the polyvalent metal salts described in Jones U.S. Pat. 2,839,405; the thiuronium salts described in Herz U.S. Pat. 3,220,839; and the palladium, platinum and gold salts described in Trivelli U.S. Pat. 2,566,263 and Damschroder U.S. Pat. 2,597,915.

Photographic elements including emulsions supersensitized in accordance with this invention can contain incorporated developing agents such as hydroquinones, catechols, aminophenols, 3-pyrazolidones, ascorbic acid and its derivatives, reductones and phenylenediamines, or combinations of developing agents. The developing agents can be in a silver halide emulsion and/ or in another suitable location in the photographic element. The developing agents can be added from suitable solvents or in the form of dispersions as described in Yackel U.S. Pat. 2,592,368 and Dunn et al. French Pat. 1,505,778.

Silver halide supersensitized in accordance with the invention can be dispersed in colloids that can be hardened by various organic or inorganic hardeners, alone or in combination, such as the aldehydes, and blocked aldehydes, ketones, carboxylic and carbonic acid derivatives, sulfonate esters, sulfonyl halides and vinyl sulfones, active halogen compounds, epoxy compounds, aziridines, active olefins, isocyanates, carbodiimides, mixed function hardeners and polymeric hardeners such as oxidized polysaccharides, e.g., dialdehyde starch, oxyguargum etc.

Photographic emulsions supersensitized with the dye combinations hereof can contain various colloids alone or in combination as vehicles or binding agents. Suitable hydrophilic materials include both naturally-occurring substances such as proteins, for example, gelatin, gelatin derivatives, cellulose derivatives, polysaccharides such as dextran, gum arabic and the like; and synthetic polymeric substances such as water soluble polyvinyl compounds, e.g., poly(vinylpyrrolidone) acrylamide polymers or other synthetic polymeric compounds such as dispersed vinyl compounds in latex form, and particularly those which increase the dimensional stability of the photographic materials. Suitable synthetic polymers include those described, for example, in U.S. Pats. 3,142,568 of Nottorf, issued July 28, 1964; 3,193,386 of White, issued July 6, 1965; 3,062,674 of Houck, Smith and Yudelson, issued Nov. 6, 1962; 3,220,844 of Houck, Smith and Yudelson,

' issued Nov. 30, 1965; Ream and Fowler 3,287,289, issued Nov. 22, 1966; and Dykstra U.S. Pat. 3,411,911; particularly effective are those water-insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates, those which have cross linking sites which facilitate hardening or curing and those having recurring sulfobetaine units as described in Canadian Pat. 774,054.

Emulsions supersensitized in accordance with this invention can be used in photographic elements which contain antistatic or conducting layers, such as layers that comprise soluble salts, e.g., chlorides, nitrates, etc., evaporated metal layers, ionic polymers such as those described in Minsk U.S. Pats. 2,861,056 and 3,206,312 or insoluble inorganic salts such as those described in Trevoy U.S. Pat. 3,428,451.

Photographic emulsions containing the supersensitizing combinations of the invention can be coated on a wide variety of supports. Typical supports include cellulose nitrate film, cellulose ester film, poly(vinyl acetal) film, polystyrene film, poly(ethylene terephthalate) film, polycarbonate film and related films or resinous materials, as well as glass, paper, metal and the like. Typically, a flexible support is employed, especially a paper support, which can be partially acetylated or coated with baryta and/ or an alpha-olefin polymer, particularly a polymer of an alpha-olefin containing 2 to 10 carbon atoms such as polyethylene, polypropylene, ethylenebutene copolymers and the like.

supersensitized emulsions of the invention can contain plasticizers and lubricants such as polyalcohols, e.g., glycerin and diols of the type described in Milton U.S. Pat. 2,960,404; fatty acids or esters such as those described in Robijns U.S. Pat. 2,588,765 and Duane U.S. Pat. 3,121,- 060; and silicone resins such as those described in Du Pont British Pat. 955,061.

The photographic emulsions supersensitized as described herein cancontain surfactants such as saponin, anionic compounds such as the alkyl aryl sulfonates described in Baldsiefen U.S. Pat. 2,600,831 and amphoteric compounds such as those described in Ben-Ezra U.S. Pat. 3,133,816.

Photographic elements containing emulsion layers sensitized as described herein can contain matting agents such as starch, titanium dioxide, zinc oxide, silica, polymeric beads including beads of the type described in Jelley et al. U.S. Pat. 2,992,101 and Lynn U.S. Pat. 2,701,245.

Spectrally sensitized emulsions of the invention can be utilized in photographic elements which contain brightening agents including stilbene, triazine, oxazole and cou marin brightening agents. Water soluble brightening agents can used such as those described in Albers et al. German Pat. 972,067 and McFall et al. U.S. Pat. 2,933,- 390 or dispersions of brighteners can be used such as those described in Jansen German Pat. 1,150,274 and Oetiker et al. U.S. Pat. 3,406,070.

Photographic elements containing emulsion layers supersensitized by the invention can be used in photo graphic elements which contain light absorbing materials and filter dyes such as those described in Sawdey U.S. Pat. 3,253,921; Gaspar U.S. Pat. 2,274,782; Carroll et a1. U.S. Pat. 2,527,583 and Van Campen U.S. Pat. 2,956,- 879. If desired, the dyes can be mordanted, for example, as described in Milton and Jones U.S. Pat. 3,282,699.

The sensitizing dyes (and other emulsion addenda) can be added to the photographic emulsions from water solutions or suitable organic solvent solutions, for example with the procedure described in Collins et al. US. Pat. 2,912,343; Owens et al. U.S. Pat. 3,342,605; Audran U.S. Pat. 2,996,287 or Johnson et al. U.S. Pat. 3,425,835. The dyes can be dissolved separately or together, and the separate or combined solutions can be added to a silver halide emulsion, or a silver halide emulsion layer can be bathed in the solution of dye or dyes.

Photographic emulsions of this invention can be coated by various coating procedures including dip coating, air knife coating, curtain coating, or extrusion coating using hoppers of the type described in -Beguin U.S. Pat. 2,681,- 294. 'If desired, two or more layers may be. coated simultaneously by the procedures described in Russell U.S. Pat. 2,761,791 and Wynn British Pat. 837,095.

Emulsions spectrally sensitized as described herein are useful in colloid transfer processes such as described in Yackel et al. U.S. Pat. 2,716,059; silver salt diffusion transfer processes such as described in Rott U.S. Pat. 2,352,014, Land U.S. Pat. 2,543,181, Yackel U.S. Pat. 3,020,155 and -Land U.S. Pat. 2,861,885; color image transfer processes such as described in Rogers U.S. Pats. 3,087,817; 3,185,567; and 2,983,606; Weyerts U.S. Pat. 3,253,915, Whitmore et al. U.S. Pats. 3,227,550; 3,227,- 551 and 3,227,552; and Land U.S. Pats. 3,415,644; 3,415,- 645; 3,415,646; and imbibition transfer processes as described in Minsk U.S. Pat. 2,882,156.

Silver halide emulsions containing the supersensitizer combinations of this invention can be used in elements designed for color photography, for example, elements containing color-forming couplers such as those described in Frolich et al. U.S. Pat. 2,376,679; Vittum et al. U.S. Pat. 2,322,027; Fierke et al. U.S. Pat. 2,801,171; Godowsky U.S. Pat. 2,698,794; Barr et al. U.S. Pat. 3,227,554 and Graham U.S.. Pat. 3,046,129; or elements to be developed in solutions containing color-forming couplers such as those described in Mannes and Godowsky U.S. Pat. 2,252,718; Carroll et al. U.S. Pat. 2,592,243 and Schwan U .8. Pat. 2,950,970.

Exposed photographic emulsions of this invention can be processed by various methods including processing in alkaline solutions containing conventional developing agents such as hydroquinones, catechols, aminophenols, 3-pyrazolidones, phenylenediamines, ascorbic acid derivatives, hydroxylamines, hydrazines and the like; web processing such as described in Tregillus et al. U.S. Pat. 3,179,517; stabilization processing as described in Yackel et al. Stabilization Processing of Films and Papers, PSA Journal, vol. 1613, August 1950; monobath processing as described in Levy Combined Development and Fixation of Photographic Images With Monobaths, Phot, Sci. and Eng., vol. 2, No. 3, October 1958, and Barnes et al. U.S. Pat. 3,392,019. If desired, the photographic emulsions of this invention can be processed in hardening developers such as those described in Allen et al. U.S.. Pat. 3,232,- 761; in roller transport processors such as those described in Russell U.S. Pat. 3,025,779; or by surface application processing as described in Example 3 of Kitze U.S. Pat. 3,418,132.

The silver halide emulsions supersensitized by the dye combinations of this invention can be used for making lithographic printing plates such as by the colloid transfer of undeveloped and unhardened areas of an exposed and developed emulsion to a suitable support as described in Clark et al. U.S. Pat. 2,763,553; to provide a relief image as described in Woodward U.S. Pat. 3,402,045 or Spencer U.S. 'Pat. 3,053,658; to prepare a relief printing plate as described in Baxter et al. U.S. Pat. 3,271,150.

The following examples are included for a further understanding of this invention. In these examples the dyes are identified by the number given in Table A above.

Example 1 Dyes I through VIII are added to separate portions of a sulfur and gold sensitized silver bromoiodide gelatin emulsion in which the halide is approximately 2.1 mole percent iodide, at the concentrations listed in Table I. To portions of the sensitized emulsions are added Calcofluor White MR, the tradename for a his [s-triazin-2-ylamino] stilbene-2,2'-disulfonic acid, sodium salt at 200 mg. mole of silver (designated stilbene in Table I), or the combination of the stilbene and 4-hydroxy-6-methyl-1,3,3a,7- tetrazaindene (designated azaindene in Table I) at 2.0 grams per mole of silver. The emulsion samples are coated on a cellulose acetate film support for 600 mg. silver and 1342 mg. gelatin per square foot. The coatings are exposed on an Eastman IB Sensitometer through Kodak Wratten Filters 35 +38A and a filter which absorbs infrared radiation (i.e., radiation over about 700 nm., such as a Chance Glass CG Filter) and Kodak Wratten Filter 89B to a tungsten light source, developed 4 minutes at about 20 C. in Kodak D-19 developer, fixed, washed and dried. Relative speeds are given in Table I for blue (Wratten 35+38A+CG) and infrared (Wratten 89B) filter exposures. These Wratten filters are described in Kodak Wratten Filters for Scientific and Technical Use, published by the Eastman Kodak Company, 22nd edition, 1966.

TABLE I Cone, Relag. per tlve Relative Ag blue infrared mole Addenda speed speed Fog 0. 2 100 100 40 0.2 Stilbene 151 166 .50 0. 2 Stilbene plus azainden 191 132 12 04 100 100 45 .04 Stilbene 316 295 31 04 Stilbene plus azaindene-. 331 159 04 4 100 100 23 871 3, 720 15 832 1, 450 03 .2 100 100 14 02 Stilbene 832 159 16 .02 Stilbene plus azaindene.-. 209 182 04 02 100 100 15 02 Stilbene 132 617 22 02 Stilbene plus azaindene..- 145 575 09 02 100 100 02 Stilbene 1, 320 479 50 02 Stilbene plus azaindene..- 2, 090 240 04 .02 100 .69 .02 Stilbene 200 1, 000 .29 02 Stilbene plus azalndene..- 550 575 06 .02 100 100 2.20 .02 Stilbene 1, 510 11,000 72 02 Stilbene plus azuindene-.. 2, 000 11, 000 30 The data in Table I demonstrates the efiective supersensitization of the tricarbocyauines employed herein by sulfonated polynuclear organic compounds. The data also shows that fog in such supersensitized emulsions, which are prone to enamine dye-produced fog, can be reduced by employing an azaindene in the emulsion. The activity of reducing agents as supersensitizers for emulsions containing enamine tricarbocyanine dye is illustrated in Example 2 below.

Example 2 Tricarbocyanine dyes used in the invention are added to portions of a gelatin silver bromoiodide emulsion containing 0.77 mole percent iodide of the type described in Trivelli and Smith, Phot. Journal, 79, 330 (1939). To

portions of the sensitized emulsions are added Calcofiuor White MR (stilbene) at 200 mg. per mole of silver and the reducing agent at 200 mg. per mole of silver or the combination of Calcofiuor White MR and reducing agent as shown in Table II. After digestion at 52 for 10 minutes, the emulsion samples are coated at a coverage of 432 mg. silver per square foot on a cellulose acetate film support. A sample of each coating is exposed on an Eastman IB Sensitometer through a Kodak Wratten 89B filter to determine infrared speed, developed for 3 minutes at C. in Kodak developer D-19, fixed, washed and dried. The results are set out in Table II and show the supersensitization by both the stilbene and reducing agent alone, and the superadditive efiect of their combination. Fog was acceptable (less than .08) on all coatings, and is not given in the table.

TABLE 11 Relative infrared Dye Addenda Speed 100 X Asorbic acid 120 X Stilbene 330 X Stilbene plus ascorbic acid o XI 10o XI Stilb e 252 XI PHR- (plperidino hexose reductone). 3 XI.-. Stilbene plus PER 416 II 100 242 200 416 100 XIII stilbene 20g XIII PH'IB (5-pheuyl-Zt-hydroxy-tetromrmde mono 142 benzoate) Stilbene plus PH'IB... 3 100 195 P R 110 Stilbene plus PHIL... 230 XV 100 XV Stilbene. 250 PI-IR 160 Stilbene plus PH ig Stilber 230 XVI Ascorbic acid 160 XVI Stilbene plus ascorbic acid. 272 XVII 100 XVII Stilbene 156 Ascorbic acid 170 Stilbene plus as rbic gg III Stilbene 190 XVIII Asc rbic acid 170 XVIII. stilb e plus ascorbic acid p83 XIX, Stiibepn 220 IX Ascorbic acid 170 XIX Stilbene plus ascorbic aci 36% XX. XX Stilben 220 XX Ascorbic acid 200 XX Stflbene plus ascorbic acid i3? XXI XXI Stiibene. 795 XXI Ascorbic acid 316 XXI Stilbene plus ascorbic aci 891 XXII 100 XXII-.. Stilbene 601 XXII Ascorbic acid 126 XXII Stilbene plus ascorbic acid 631 The results in Table II shows that photographic emulsions containing enamine tricarbocyanine dyes of the type described above are supersensitized with either sulfonated aromatic organic supersensitizer, or a silver halide reducing agent. The data further shows that the combination of sulfonated aromatic organic supersensitizer with silver halide reducing agent produces a synergistic or superadditive effect. Generally similar results are obtained when the reducing agents employed in Example 2 are replaced with other benzenes, lactones, tetronimides, pyronimides,

'furans and pyrroles, each of which contain at least two hydroxy groups.

16 Example 3 Various sulfonated polynuclear aromatic supersensitizers are added, at concentrations of 200 mg. per mole of silver, to silver halide emulsion of the type used in Example 2 which is spectrally sensitized with Dye II, and the emulsions are coated and tested by the exact procedure of Example 2. The results are shown in Table III.

TABLE III Relative infrared Stilbene: speed None Calcofluor White MR 166 The results in Table III show that a wide variety of sulfonated polynuclear aromatic organic compounds supersensitize photographic silver halide emulsions containing an enamine tricarbocyanine dye.

Example 4 illustrates the supersensitization of emulsions containing enamine tricarbocyanine dye with an azaindene. The preferred combination of enamine tricarbocyanine dye, an azaindene and sulfonated organic supersensitizer is also illustrated in Example 4.

Example 4 Coatings are prepared as in Example 1 except using a sulfur and gold sensitized silver bromoiodide gelatin emulsion, in which approximately 2.5 mole percent of the halide is iodide, and coated at 250* mg. silver and 574 mg. gelatin per square foot. The emulsion comprises cubic grains, having an average size of about .3 micron, prepared as described in British Patent 1,156,193 published June 25, 1969, and corresponding Illingsworth U.S. patent application Ser. No. 500,366, filed Oct. 21, 1965. Azaindene and combinations of azaindene and sulfonated aromatic organic supersensitizers are added to the emulsion. The coatings are exposed and processed as described in Example 1. The results are shown in Tables IV and V below. In Tables IV and V, supersensitizer A is Calcofluor White MR (identified in Example 1); supersensitizer B is Leucophor B, which is the tradename for a bis(striazin 2 ylamino)stilbene-2,2-disulfonic acid, sodium salt; supersensitizer C is 4,4'-bis[2-phenoxy-4-(2-hydroxyethylamino)-l,3,5-triazin 6 ylamino]stilbene-2,2-disulfonic acid, disodium salt; supersensitizer D is 3,7-bis-(4- methoxy-S-sulfobenzamido -dibenzothiophenedioxide, sodium salt; supersensitizer E is chrysene-6-sulfonic acid, sodium salt; and, supersensitizer F is 4,4'-bis[4,6-bis(ochloroanilino) 2 triazinylamino] stilbene-2,2'-disulfonic acid, disodium salt. supersensitizer Z is 4-hydroxy-6- methyl-l,3,3a,7-tetrazaindene.

TAB LE IV Super Blue exposure Infrared exposure sensitizer, Tetrazalnmg. per dene, g. per Relative Relative Dye, mgJmole Ag mole Ag mole Ag speed Gamma Fog speed Gamma Fog None 229 3. 8 06 100 4. 3 08 100 5. 5 08 2 363 4. 1 14 269 4. 9 l4 2. 0 240 4. 3 08 309 4. 7 08 2. 0 302 4. 0 10 380 4. 8 10 2. 0 324 4. 4 10 417 5. 2 11 100 3. 66 38 100 4. 2 38 2. 0 398 3. 74 22 141 4. 1 22 2. 0 251 4. 5 398 4. 8 10 2. 0 316 4. 1 10 289 5. 0 10 2. 0 316 4. 2 .10 389 6.8 .10 295 3. 70 04 l 04 123 1. 60 04 17 4. 25 04 346 4. 35 04 794 3. 50 03 282 3. 27 04 23 4. 30 04-. 468 4. 04 1, 02A 2. 80 05 TABLE V Incubation 1 wk. 120 F. and Fresh 50% relative humidity Relative Relative Super sensitizer, infrared infrared Dye, 40 mgJmole Ag mg./m0le Ag speed Gamma Fog speed Gamma Fog I 100 5. 50 08 123 5. 90 11 I ,000) 269 4. 90 14 224 5. 15 I. Z(2,000)+A(300) 309 4. 70 08 339 5. 40 09 I. Z(2,000)+B(300) 380 4. 80 10 372 5. 35 10 I. Z(2,000)+C(300) 417 5. 20 11 457 5. 15 09 II 100 4. 70 38 89 4. 48 II 141 4. 10 22 91 4. 70 28 II 486 4. 80 10 550 5. 26 II. 331 4. 60 14 331 5. 20 25 II 417 5. 13 479 5. 20 13 I 234 5. 60 08 209 6. 10 07 II 138 4. 20 22 100 4. 90 22 II 276 4. 30 26 107 4. 40 31 The results in Tables IV and V above establish that azaindenes supersensitize tricarbocyanine enamine dyes, and that particularly good results are obtained when the combination of sulfonated organic supersensitizer is used with an azaindene. Generally similar results are obtained when the azaindene supersensitizer used in Example 4 above is replaced with a similar quantity of 7-hydroxy- 1,2,3,4,'6-pentazaindene, 2,4 dihydroxy-G-methyl-1,3a,7- triazaindene or other azaindenes of the type referred to above.

Emulsions supersensitized as described herein are particularly useful in high definition aerial color films, which can comprise a film support having coated thereon the following layers:

(1) An antihalation layer containing a dispersion in gelatin of gray colloidal silver,

(2) A fast, blue-sensitive gelatino-silver bromo-iodide emulsion containing a dispersion of a nondiffusing a-pivalyla-phenoxyacetanilide nondifrusible, yellow-dye-forming coupler such as is described in U.S. Patent 3,408,194, column '6,

(3) A gelatin layer containing 2,5-dioctylhydroquinone,

(4) A gelatin layer containing a bleachable cyan-colored dye,

'(5) A slow red-sensitized buried iodide gelatinosilver bromoiodide emulsion in which the silver halide grains have a core of silver bromoiodide surrounded with a shell of silver bromide that is essentially free of silver iodide, and dispersed in this emulsion a nondiifusible l-hydroxynaphthamide nondiffusible cyan-dye forming coupler of U.S. lPat. 2,474,293, column 2, and a nonditfusible 2,5-disubstituted phenolic nondifiusible cyandye-forming coupler that is an analog of a coupler in U.S. Pat. 2,895,826, column 3,

('6) A gelatin layer containing 2,5-dioctylhydroquinone,

(7) A gelatin layer containing a bleachabe-magentacolored dye,

(8) A slow, green-sensitized buried iodide gelatino-silver bromoiodide emulsion in which the silver halide grains have a core of silver bromoiodide surrounded with a shell of silver bromide that is essentially free of silver iodide, and dispersed in this emulsion an nonditfusible 3-benzamido-l-phenyl-S-pyrazolone nondiifusible magenta-dyeforming coupler, of U.S. Pat. 2,908,573, column 3,.

(9) A gelatin layer containing a bleachable-yellowcolored dye, and

(10) A gelatin layer containing a dispersion of an ultraviolet-absorbing agent, such as is described in U.S. Pat. 3,250,617 in Table A, column 4, and a mordant produced by reacting aminoguanidine and polymeric oxo-compound, such as is described in U.S. Pat. 2,882,156.

The buried iodide emulsions are advantageously prepared by forming an iodide-rich base of silver bromoiodide during the first 15 percent of precipitation followed by the formation of an iodide-free silver halide phase thereover, and controlling the pAg at a constant level to obtain the desired grain size which is preferably less than about .75 micron and advantageously under .5 micron in diameter.

The element described above is exposed in an airborne aerial camera to a light image of the terrain below, and processed in a color process, such as that described in Graham et al., U.S. Pat. 3,046,129, issued July 24, 1962, column 23, line 34 through column 24, line 27. The color developed image reproduction has improved definition compared to the definition of image reproductions made of the same exposure on prior art aerial color film.

Example 5 illustrates the supersensitizing combination of a tricarbocyanine enamine dye together with sulfonated aromatic compound, silver halide reducing agent and azaindene.

Example 5 Three coatings of a cubic grain gelatin silver halide emulsion on a cellulose acetate film support are prepared as described in Example 4. Each emulsion contains 2 grams of 4-hydroxy-6-methyl-l,3,3a,7-tetrazaindene per mole of silver. Two of those three emulsions also contain mg. per mole of silver of Dye II and 1000 mg. per mole of silver of stilbene F, 4,4-bis-[(4,6-bis-o-chloroanilino-s-triazin-Z-yl)amino]-2,2'-stilbenedisulfonic acid, disodium salt. One of the emulsions containing Dye II and stilbene F also contains 500 mg. per mole of silver of ascorbic acid. The three coatings are exposed and processed as in Example 4. The results are shown in 20 phenylene linkage; R and R taken separately each represents a member selected from the group consisting of alkyl and aryl and taken together, R and R represents a morpholino group, a thiomorpholino group, a piperidino group, a piperazinyl group a Table V I below. 5 pyrroliolinyl group, and indolinyl group, a tetrahydro- TABLE VI Mg. per Mg. per G. per mole Ag mole Ag mole Ag Relative Relative Mg. per mole stilbene ascorbic tetrazablue infrared Ag Dye II F acid indene speed speed Fog u 0 2 341 0.03 1,000 o 2 100 100 0.03 1, 000 500 2 389 447 0. 1a

The results in Table VI above show that photographic quinoyl group and a decahydroquinoyl group; Z silver halide emulsions are eflectively supersensitized with and Z each represents a thiazole nucleus, a oxazole the combination of an enamine tricarbocyanine dye, sulnucleus, a selenazole nucleus, a thiazoline nucleus, fonated aromatic compound, silver halide reducing agent a pyridine nucleus, a quinoline nucleus, a 3,3-dialkyland azaindene. indolenine nucleus and an imidazole nucleus; and,

Infrared sensitization is generally higher when cubic X represents an acid anion; and, grain silver halide emulsions are employed, rather than at least one supersensitizer selected from the group octahedral silver halide emulsion grains. Especially useful consisting of: antifoggants for infrared sensitized cubic grain emulsions a water-soluble sulfonated organic supersensitizer repinclude 3,3'-alkylene'bis(benzothiazolium salts) such as resented by the following formula: 3,3-decamethylenebis(benzothiazolium bromide), or a diselenide antifoggant such as o,o-diselenobis(N-methylacetanilide, or a combination of these two antifoggants. Such antifoggants are especially useful when the emulsion D1 0 M also contains a color coupler, such as one of the following couplers: wherein D represents a 1,3,5 triazin 6 ylamino OH group, D represents sulfonated benzene substituted l with a 1,3,5-triazin-2-ylamino group and M represents a member selected from the group consisting of hydrogen and a cation; t-C H -@OCHOONH a dihydroxy substituted silver halide reducing agent 40 supersensitizer selected from the group consisting of JhHn-t the benzenes, lactones, tetronimides, pyronimides, 0H furans and pyrroles, each of which contain at least I two hydroxy groups; and,

coNH- cH, .o-@-cmn-t an azaindene selected from the group consisting of the hydroxy and amino substituted triazaindenes, tetra- C;H t azaindenes and pentaazaindenes.

wherein n and m each represents an integer of from 1 to 2; R and R are selected from the group consisting of an alkyl group and an aryl group; Q represents the atoms necessary to complete a divalent linkage selected from the group consisting of an ethylene linkage, a trimethylene linkage and an ortho- 2. A light-sensitive photographic silver halide emulsion sensitized with a supersensitizing combination comprising: a tricarbocyanine dye having the following formula:

wherein n and m each represents an integer of from 1 to 2; R and R are selected from the group consisting of an alkyl group and an aryl group; Q represents the atoms necessary to complete a divalent linkage selected from the group consisting of an ethylene linkage, a trimethylene linkage and an orthophenylene linkage; R and R taken separately, each represents a member selected from the group consisting of alkyl and aryl, and, taken together, R and R represents a morpholine group, a thiomorpholino group, a piperidino group, a piperazinyl group, a pyrroliolinyl group, an indolinyl group, a tetrahydroquinolyl group and a decahydroquinoyl group; Z and Z each represents a thiazole nucleus, an oxazole nucleus, selenazole nucleus, a thiazoline nucleus, a pyridine nucleus, a quinoline nucleus, a 3,3-

dialkylindolenine nucleus and an imidazole nucleus; and, X represents an acid anion; and, a supersensitizing combination comprising:

a water-soluble organic compound represented by the following formula:

SOaM wherein D represents a 1,3,5-triazin-6-ylamino group, D represents sulfonated benzene substituted with a 1,3,5-triazin-2-ylamino group and M represents a member selected from the group consisting of a hydrogen atom and a cation; and, an organic reducing agent supersensitizer containing at least two hydroxyl substituents selected from the class consisting of a dihydroxyarylene; a 'y-lactone; a 3-hydroxytetronamide; 3,4,5-trihydroxy-S,6-dihydropyrronimide and, an aminohexose reductone wherein the amino moiety of said reductone has the following formula:

R12 Rll l] wherein R and R each are selected from the group consisting of alkyl radicals and, taken together with the nitrogen atom to which they are attached, the necessary atoms to form a nitrogen-containing heterocyclic radical. 3. A light-sensitive photographic silver halide emulsion sensitized with a supersensitizing combination comprising: a tricarbocyanine dye having the following formula:

wherein n and m each represents an integer of from 1 to 2; R and R are selected from the group consisting of an alkyl group and an aryl group; Q represents the atoms necessary to complete a divalent linkage selected from the group consisting of an ethylene linkage, a trimethylene linkage; and an orthophenylene linkage; R and R taken separately, each represents a member selected from the group consisting of alkyl and aryl and, taken together, R and R represent a morpholino group, a thiomorpholino group, a piperidino group, a piperazinyl group, a pyrroliolinyl group, an indolinyl group, a tetrahydroquinoyl group and a decahydroquinoyl group; Z and Z each represents a thiazole nucleus, an oxazole nucleus, a selenazole nucleus, at thiazoline nucleus, a pyridine nucleus, a quinoline nucleus, a 3,3-dialkylindolenine nucleus and an imidazole nucleus; and, X represents an acid anion; and, a supersensitizing combination comprising:

a water-soluble organic compound represented by the following formula:

wherein D represents a 1,3,5-triazin-6-ylamino group, D represents sulfonated benzene substituted with a 1,3,5-triazin-2-ylamino group and M represents a member selected from the group consisting of a hydrogen atom and a cation; and,

an azaindene selected from the group consisting of the hydroxy and amino substituted triazaindenes, tetrazaindenes and pentazaindenes.

4. A light-sensitive photographic silver halide emulsion as defined in claim 2 wherein, in the formula for said tricarbocyamine dye, n and In each represents 1; R and R each represents a lower alkyl group of from 1 to 4 carbon atoms; Q represents an ethylene linkage; R and R taken separately, each represents a member selected from the group consisting of alkyl and aryl, and, taken together, R and R represents the atoms required to com plete, with the nitrogen atom to which they are attached, a member selected from the group consisting of a morpholino group, a thiomorpholino group, a piperidino group, a piperazinyl group, a pyrrolidinyl group, an indolinyl group, a tetrahydroquinoyl group and a decahydroquinoyl group; and, Z and Z each represents the atoms required to complete a nucleus selected from the group consisting of a benzoxazole nucleus and a benzothiazole nucleus.

5. A light-sensitive photographic silver halide emulsion as defined in claim 3 wherein, in the formula for said tricarbocyanine dye, n and In each represents 1; R and R each represents a lower alkyl group of from 1 to 4 carbon atoms; Q represents an ethylene linkage; R and R taken separately, each represents a member selected from the group consisting of alkyl and aryl, and, taken together, R and R represent the atoms required to complete, with the nitrogen atom to which they are attached, a member selected from the group consisting of a morpholino group, a thiomorpholino group, a piperidino group, a piperazinyl group, a pyrrolidinyl group, an indolinyl group, a tetrahydroquinoyl group and a decahydroquinoyl group; and, Z and Z each represents the atoms required to complete a nucleus selected from the group consisting of a benzoxazole nucleus and a benzothiazole nucleus, and said azaindene is a tetraazaindene.

6. A light-sensitive photographic silver halide emulsion comprising cubic silver halide grains sensitized with a supersensitizing combination comprising a dye having the formula:

wherein n and m each represents an integer of from 1 to 2; R and R are selected from the group consisting of an alkyl group and an aryl group; Q represents the atoms necessary to complete a divalent linkage selected from the group consisting of ethylene linkage, a trimethylene linkage and an orthophenylene linkage; R and R taken separately, each represents a member selected from the group consisting of alkyl and aryl and, taken together, R and R represent a morpholino group, a thiomorpholino group, a piperidino group, a piperazinyl group, a pyrroliolinyl group, an indolinyl group, a tetrahydroquinoyl group and a decahydroquinoyl group; Z and Z each represents a thiazole nucleus, a oxazole nucleus, a selenazole nucleus, a thiazoline nucleus, at pyridine nucleus, a quinoline nucleus, a 3,3-dialkylindolenine nucleus and a imidazole nucleus; and, X represents an acid anion; and, a triazaindene, a tetraazaindene or a pentazaindene.

7. A light-sensitive photographic silver halide emulsion comprising cubic silver halide grains sensitized with a supersensitizing combination comprising a dye having the formula:

23 separately, each represents a member selected from the group consisting of alkyl, and aryl and, taken together, R and R represent a morpholino group, a thiomorpholino group, a piperidino group, a piperazinyl group, a pyrroliolinyl group, an indolinyl group, a tetrahydroquinoyl group and a decahydroquinoyl group; Z and Z each represents a thiazole nucleus, a oxazole nucleus, a selenazole nucleus, a thiazoline nucleus, a pyridine nucleus, a

. quinoline nucleus, at 3,3-dialkylindolenine nucleus and a imid-azole nucleus; and, X represents an acid anion; and, the combination of an azaindene selected from the group consisting of the hydroxy and amino substituted triazaindenes, tetrazaindenes and pentazaindenes together with a water-soluble sulfonated organic supersensitizer represented by the following formula:

wherein D represents a 1,3,5-triazin-6-ylamino group, D represents sulfonated benzene substituted with a 1,3,5-triazin-2-ylarnino group and M represents a member selected from the group consisting of hydrogen and a cation.

8. An unexposed light-sensitive photographic silver halide emulsion supersensitized with a combination comprismg:

at least one dye selected from the group consisting of:

anhydro l1 (4-ethoxycarbonylpiperazin-1-yl)- 10,12-ethy1ene-3,3'-bis(3-sulfopropyl) 5,6;5,6- dibenzothiatricarbocyanine hydroxide, triethylamine salt '11 (4 ethoxycarbonyl 1 piperazinyl)-3,3-diethyl-10,12-ethyleneoxatricarbocyanine salt 3,3-diethyl 10, 12 ethylene-11-(4-methyl-l-piperazinyl)-oxatricarbocyanine salt 3,3-diethyl 10,1'2 ethylene-l 1-(4-methyl-1-piperazinyl)-thiatricarbocyanine salt 11 (4-et'hoxycarbonyl 1 piperazinyl)-3,3'-diethyl-10,12-ethylene 5,5 diphenyloxatricarbocy- 'anine salt anhydro-1'1-(4 ethoxycarbonyl 1 piperazinyl)- 10,12-ethylene 3,3 di(3-sulfopropyl)thiatricarbocyanine hydroxide anhydro 10,12 ethylene-1I-(4-methyl-1-piperazinyl)-3,3-di(3 sulfopropyl) oxatricarbocyanine hydroxide anhydro 10,12 ethylene-l1-(4-methyl-l-piperazinyl) 3,3 di(3 sulfopropyl)thiatricarbocyanine hydroxide 1'1-(4 ethoxycarbonyl l piperazinyl)-3,3-diethyl-10,12-ethylenethiatricarbocyanine salt an'hydro 11 dibutylamino-l0,1'2-ethylene3,3'- di(3-sulfopropyl)thiatricarbocyanine hydroxide 3,3'-diethyl 10,12 ethylene-11-(l-pyrrolidinyl)- thiatricarbocyanine salt 10,12-ethylene 1,1',3,3,3',3'-hexamethyl-1l-(pyrrolidinyl)indotricarbocyanine salt 3,*3'-diethyl 10,12 ethylene-1l-piperidinothiatricarbocyanine salt 3,3-diethyl 10,12 ethylene-1l-morpholinothiatricarbocyanine salt 3,3'-diethyl 11 piperidino l 0,12-trimethylenethiatricarbocyanine salt 3,3'-diethy1 10,12 ethylene-l1-(1-indolinyl)oxatricarbocyanine salt 3,3'-diethyl 10,12 ethylene-11-['1-(1,2,3,4-tetrahydroquinolyl]oxatricarbocyanine salt l l-diethylamino -3,3' diethyl-IO,lZ-ethylenethiatricarbocyanine salt ll-diethylamino 10,12 ethylene-1,3',3,'3;3',3-

hexamethylindotricarbocyanine salt 3,3-diethyl 10,12 ethylene-11-[1-(1,2,'3,4-tetrahydroquinolyl)]-4,5;4',5 dibenzothiatricarbocyanine salt l l-diphenylamino 3,3 diethyl 10,12 ethyleneoxatricarbocyanine salt ll-dimethylamino 3,3 diethy1-10, l2-ethylenethiatricarbocyanine salt and at least one supersitizer selected from the group consisting of:

a sulfonated polynuclear aromatic supersensitizer selected from the group consisting of:

a bis[s-triazin 2 ylamino]stilbene-2,2'-disulfonic acid salt;

-4,4'-bis[(4-amino 6 anilino 8 triazin-2- yl)amino]-2,2'-stilbene disulfonic acid salt;

4,4'-bis['(4-amino 6 phenoxy-s-triazin-Z- yl)arnino]-2,2-stilbene disulfonic acid salt;

4,4'-bis(3 phenylureido)2,2' stilbene disulfonic acid salt;

4,4 bis[4,6 bis(p-sulfoanilino)-s-triazin-2- yl]-amino-2;2'-stilbene disulfonic acid salt;

4,4-bis[ (4-anilino 6 hydroxy-s-triazin-Z- y1)-amino]2,'2-stilbene disulfonic acid salt;

4,4'-bis[ (4-hydroxy 6 phenoxy-s-triazin-2- yl)-amino]2,2-stilbene disulfonic acid salt;

4,4 bis[ (4,6 bisanilino s triazin-2-yl)- amino]-2,2-stilbene disulfonic acid salt;

4,4 bis[2-phenoxy 4 (2 hydroxyethyl- 'amino)-l,3,5-triazin 6 ylaminoJstilbene- 2,2'-disulfonic acid salt;

3,7-bis(4-methoxy 3 sulfobenzamido)-dibenzothiophenedioxide salt; and

chrysene-6-sulfonic acid salt;

a reducing agent selected from the group consisting of ascorbic acid; piperidino hexose reductone; hydroquinone; and, 5-phenyl 3 hydroxytetronimide-monobenzoate; and,

4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene.

9. A light-sensitive photographic silver halide emulsion supersensitized with a combination comprising anhydro- 1 1-'( 4-ethoxycarbonyl- 1-piperazinyl)-10, 12-ethylene 3,3 di(3-sulfopropyl)thiatricarbocyanine salt; a bis[s-triazin- 2-ylamino]stilbene-2, 2'-disulfonic acid, disodium salt; and, 4-hydroxy-6-methyl-1,3,-3a,7-tetrazaindene.

10. A light-sensitive photographic silver halide emulsion comprising cubic silver halide grains sensitized with a super-sensitizing combination comprising anhydro-ll-(4- ethoxycarbonyl-l-piperazinyl) 10,12 ethylene-3,3'-di(3- sulfopropyl)-thiatricarbocyanine salt; a bis[s-triazin-2-ylamino]sti1bene-2;2-disulfonic acid, disodium salt; and, 4- hydroxy-6-metl1yl-1,3,3a,7-tetrazaindene.

References Cited UNITED STATES PATENTS 3,482,978 12/1969 Fumia et al. 961'27 3,506,655 4/1970 Jeifreys 96-l27 3,501,306 3/1970 'Illingsworth 96-407 J. IRAVIS BROWN, Primary Examiner US. Cl. X.R. 

